02- utilizing possibilities of iec 61850 and goose

7/28/2019 02- Utilizing Possibilities of IEC 61850 and GOOSE

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INTRODUCTION

Horizontal communication, or GOOSE, as it is called in theIEC 61850 standard, can be used to enhance existing

medium voltage substation automation applications. Theirst way is by simpliying and decreasing the wiring inside

medium voltage switchgear, which helps to reduce costs.The second is by implement ing a completely new

application using Ethernet and GOOSE because ignallingresponse times rom device to device can be signiicantly

aster than traditional hard-wiring rom binary outputs to

binary inputs.

Traditional ly, the signal paths between protection and

control devices have been hardwired. In these schemes, theresponse time is constrained by the auxiliary relay on/o

delay o the sending device, and correspondingly by theinput iltering on the receiving device. Both these delays

can be avoided using GOOSE. Additionally, protection andcontrol devices oten have a limited number o binary inputs

and outputs due to cost and space constraints. WithGOOSE, a higher number o virtual inputs and outputs can

be used without additional device or wiring costs.

Enhanced perormance and capacity compared with theadditional costs in traditional systems open up thepossibility o introducing new and improved unctionality,

such as aster busbar protection and co-ordinated arcprotection.

Furthermore, GOOSE enables a more comprehensive

supervision o the system. With a hard-wired system, it isnot possible to know i a wire really is connected and

working, whereas all GOOSE connections are constantlymonitored, and any anomalies are reported to the substation

automation system. Thus, the receiving device can take

corresponding actions, such as shiting into ail-sae mode

or blocking some unctionality. Additionally, devices in testmode can be indicated using GOOSE communication and

thereore actions can be taken in the receiving devices. Thismakes testing easier and saer.

SIMPLIFIED WIRING

Traditional hard -wired medium voltage switchgear systemscontain extensive I/O wiring, connecting protection and

control devices, or two main purposes:

1. Signalling between switchgear bays. Typical signalsinclude breaker, disconnector and earthing switch status

signals, service and interlocking position inormation, andprotection start signals.

2. Signalling to and rom external systems, or exampleto RTUs or other automation systems. As well as most

o the signals listed above, current, voltage and powermeasurement signals are also included.

Extensive signal wiring constitutes a signiicant cost over

the entire lie cycle o the switchgear installation. Table 1

reveals the extent to which hardwired I/O signal wiring isneeded in a conventional 10-bay medium voltage switchgearinstallation.

Table 1. Amount of I/O wiring in traditional hardwired MV switchgear

system

Utilizing IEC 61850 and the GOOSE acility in modern protectionand control devices, a vast number o signals can be transerred

using Ethernet instead o hardwiring. However, Table 1 reveals that70% o the signal connections are to external systems. Though

modern automation systems and load management controllers

This document describes the utilization of some new

features offered by IEC 61850, Communication Networks

and Systems in Substations. In particular, the paper looks

at how horizontal communication, commonly known as

GOOSE communication, between protection and control

devices can be used to improve the reliability and

performance of the system. Besides describing generic

improvements in capacity, performance and reliability, the

paper presents a practical GOOSE application, i.e.

blocking based busbar protection.

Utilizing possibilities o IEC 61850 and GOOSEHakala-Ranta, Rintamki, Starck

CIRED 2009, Paper 0741

Number of IO wires

From/To

Protectionand

ControlIEDs

From/Toother

Devices

Total

Intebay signalling 104 116 220

Automation system 85 47 132Other externals, i.e. load

management system

383 252 635

Total 572 415 987


2/42 CIRED 2009 Paper 0741 | Utilizing possibilities of IEC 61850 and GOOSE

also incorporate GOOSE capability according to IEC 61850, the-

reby enabling high-perormance integration without hardwiring, ithas to be noted that most o the traditional feldbusses and com-

munication protocols, such as Modbus, and even the IEC61850-8-1 client/server profle do not perorm properly in deman-

ding load management applications.

Signifcant savings can be achieved i only some o these signals

are based on IEC 61850 GOOSE instead o traditional wiring. Aswell as the obvious reduction in material and direct labour costs,ewer wires result in savings rom several other areas.

The use o GOOSE signalling over an Ethernet bus instead o

binary signalling over hardwired cables decreases the number owiring diagrams required, which enables the switchgear vendor to

standardize the design and thereore streamline the productionprocess. The nature o the Ethernet makes it possible to use auto-

matic test tools to test the signal paths, whereas a hardwiredsolution would need signifcant manual intervention even in an

automated approach.

Extensive wiring is not costly in the initial installation, but becausethe whole switchgear is split into separate panels or transporta-

tion, inter-panel wires have to be reconnected and possiblyretested on site.

Furthermore, late stage or even on-site signal and logic additions

are possible with GOOSE without having to install extra signalwires or use spare I/O channels in the protection and control

devices.

PERFORMANCE OF A GOOSE SOLUTION

One o the essential preconditions or using GOOSE is thatit perorms adequately compared with a hardwired solution.In addition, due to the non-deterministic nature o Ethernet,

reliability has to be guaranteed under diicultcommunication load conditions. Both perormance and

reliability can be managed i the protection and controldevices are properly designed to use GOOSE signalling in

applications as critical as those o hardwired signals.

Performance

In a hardwired system, signal propagation delay

perormance is constrained by three main actors:

1. Output circuitry delay, e.g. make or break delay oauxiliary signalling relays, typically 8-10ms

2. Input handling and iltering time in the receivingdevice. Oten there is an additional ilter delay to

suppress spikes etc. caused by electromagneticdisturbance. This is normally adjustable in the

protection and control devices, but typical total values,including the input conditioning delay, are in the range

10-50 ms.3. Application cycle time o the protection and control

device, i.e. the requency indicating how oten the

device processes its I/O signals. Typically 1-50 ms.

By using GOOSE and Ethernet communication, the delay

types #1 and #2 can be omitted, but the communication

propagation delay needs to be added. As a consequence, i

GOOSE support is implemented properly and it ulils thehardest criteria o IEC 61850-5, the total propagation delay

can be signiicantly lower in GOOSE systems than intraditional systems. This beneit is used in protection schemes

described later in this document.

Testing the performance: blocking the incomer

protectionFig. 2 shows a typical distribution network primary substationwith two protection and control devices. Fault

currents are injected rom a network simulator usingrecorded ault current patterns and a simple network model.

The task is to measure how quickly the - incomer protectioncan be blocked in the event that the ault is on the outgoing

eeder.

Fig 2. Test arrangement to study blocking performance

Using a GOOSE based setup, the time taken to block the

protection stage on device A ater the ault current was

injected was 1520 ms. In contrast, with the sameprotection settings and a reasonable input ilter time o 5 mson device A, and using wiring rom device A to B, the time

measured was around 47ms.

To achieve minimum operating time but maintainselectivity, the operation delay o the high-set overcurrent

protection stage in device A needs to be set properly.Reduced signal propagation delay can be used to improve

the protection scheme.

Reliability under communication load

Even in a well designed system the devices mightexperience background Ethernet traic, such as sporadicqueries by engineering tools. And most signiicantly, every

untargeted device on the same LAN segment will see allthe multicast/broadcast traic - generated, or example, by

GOOSE messages - intended or other devices. The eecto this additional communication load on GOOSE response

times should be minimized. With modern designs andtechnology, e.g. using message iltering on the hardware

level, even high communication loads can be managed. Inthe ollowing diagram the GOOSE response time

distribution is depicted under a communication loading o

2,000 GOOSE messages per second on the network. Thesemessages were intended (subscribed by) or the devicesunder test. The response time was measured by two ABB

REF615 devices.

Busbar

IEC 61850

Load110/20 kV16 MVA

A B

2) The relay receivesthe signal and

PHIPTOC1 stageblocks

0.8 MVA 200/0.4 kV1 MVA

1) PHIPTOC1 stage

starts and send block

signal to IED A

Test 1 (three phase fault, resistance 0 and

block signal is transferred by Goose)

Test 2 (three phase fault, resistance 0 and

block signal is transferred through the wiring)

AHMCMK 120 (3 km)


3/4Utilizing possibilities of IEC 61850 and GOOSE | CIRED 2009 Paper 0741 3

Fig 3. GOOSE response time at 2000 msg/s background communica-

tion load, a total of 225 test messages.

It can be seen that the response time perormance ulfls the stan-

dard criteria (specifed in IEC 61850-5, Type 1A, Class P2/3 mes-sages, 3 ms) even under heavy load conditions. It must be noted

that the times measured include up to 2.5 ms o the applicationprocessing cycle time o the REF615 device. This time is not

accounted or in the perormance measurements specifed in IEC

61850-5, but has to be taken into account in actual applications.

SUPERVISING THE SIGNAL QUALITY AND

STATUS OF HORIZONTAL COMMUNICATION

The strength o using IEC 61850 peer-to-peer communication

compared to traditional hard wiring can be ound inthe supervision unctionality and data quality handling.

GOOSE supervision works as illustrated in Fig. 4 . Datasending is event based and when a change in GOOSE data

occurs, a message is sent multiple times to the network toensure the data has been received. Message repetition starts

at Tmin and continues with IED speciic curve until the

message sent goes to heart-beat cycle Tmax. I the receivingIEDs do not get the message within a certain time (e.g.2*Tmax) the user is notiied. The IED application can then

handle the situation by changing the application values toail-sae ones, or example. The signal low between bays

with hard-wired connections is, however, not supervised.Thereore GOOSE signi icantly improves saety.

Additionally GOOSE data is sent with quali ty attributeswhich are used when interpreting the input value at the

receiver side. This inormation is used in the runningsubstations, as well as in switchgear actory and site tests.

Fig 4. GOOSE Supervision

In running substations the quality attributes are used todetect ailures in other IEDs and to act accordingly. For

example, i an IED sending GOOSE data has an oscillating

input, the data rom this input is marked as oscillating andthe IED receiving the data does not update the applicationdue to invalid data. Instead the preconigured ail-sae value

is used, thus making the system saer.

Quality handling can also be used in the switchgear actory

and site testing phases by setting the IEDs to Test orTest/Blocked mode. See Table 2.

Table 2. GOOSE Test and Test/Blocked quality handling

When testing GOOSE connections between IEDs in Test mode itis assumed the connections to physical processes are not active

as IED outputs to processes are activated according to the appli-cation. In Test/Blocked mode the IED outputs are not activated.

Both the sender and the receiver IEDs must be set to Test modeto be able to utilize GOOSE signal testing between bays.

BLOCKING-BASED BUSBAR PROTECTION

USING GOOSE

The GOOSE service o the IEC 61650 standard can be used

in blocking-based busbar protection schemes. In this newapproach the conventional hard-wired blocking signal pathsbetween the switchgear cubicles are replaced with a

substation-wide Ethernet LAN.

Fig 5. A fast busbar protection scheme based on ABBs new 615 se-

ries of protection and control IEDs, a station-wide Ethernet LAN and

GOOSE services

IED in Test mode IED in Test/Blocked

mode

Outputs to

process

Yes No

GOOSEoutput

Sent data quality isflagged with test. If IED

logic is set to Test

mode, GOOSE message

header Test bit is

activated

Sent data quality isflagged with

test/blocked. If IED

logic is set to Test

mode, GOOSE message

header Test bit is

activated

GOOSE

input

Outputs to process are

active only if received

GOOSE data is flagged

with Test quality mode

Received GOOSE data

updates the IED

application but the

output from process to

process is not activated

32

9285

16

0

10

20

30

40

50

60

70

80

90

100

1 2 3 4

ms

Tmax Data Tmin Tmaxe.g.10s

change e.g.2 ms

e.g.10s

Feeder

Incomer

LAN (IEC 61850-8-1)


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CIRED

2009Paper0741

Copyright2009IET.Publishedwithpermission.

Fast and reliable busbar protection

By using GOOSE messaging an operational speed gain obetween 30 and 50% can be achieved when compared with the

operating speed o classical hardwired, blocking-based busbarprotection schemes. This advantage is entirely attributed to the

speed and reliability o the GOOSE service.

Blocking based protection schemes are well-known and widely

accepted. When a ault occurs on an outgoing eeder, the protec-tion and control IEDs o both the incoming eeder and the aultyoutgoing eeder start. On starting, the IED o the outgoing eeder,

however, blocks the ast-acting stage o the incoming eeder IED.On the contrary, should a ault arise on the busbar system, the

outgoing eeder IEDs will not start and the incoming eeder IED isallowed to operate ater a short coordination time delay and trip

the CB o the incoming eeder.

By transerring GOOSE messages between the IEDs intercon-nected with a local area network (LAN), the blocking signals can

be sent directly rom IED to IED without additional delays rom

the auxiliary relays or input flters. In complex busbar systems theblocking signals have to be routed to several objects. For hardwi-red schemes this means inserting auxiliary relays, which delays the

blocking circuit. This additional delay must be considered whenthe total operating time o the protection is determined.

By applying GOOSE messaging, blocking signals can be transer-

red to all the involved IEDs at once, and the ones to be blockedpick up the signal rom the message stream. When using GOOSE

messaging the total operating time o the busbar protection is in-dependent o the number o protection and control IEDs involved

and the complexity o the busbar system.

Adaptive and flexible protection

Applying GOOSE services to exible REF615 eeder protection

and control IEDs allows the busbar protection to beneft rom themultiple protection stages o the IEDs. REF615 contains separate

protection stages or the individual protection unctions. In thisway compromises stemming rom conicting requirements on a

certain stage can be avoided when determining setting valuesor the protection unctions. These circumstances are particularly

benefcial in busbar protection applications based on the blockingprinciple. The settings o the IED stage issuing blocking signals

can be reely determined rom the magnitude o the short-circuit

current, switching inrush current and the starting current o theeeder. The reach o the protection stage in a ault situation doesnot need to be considered when the protection settings are

determined. These eatures make blocking schemes a useul andeective means o implementing high-speed busbar protection in

distribution substations.

Fig. 6. Comparative table outlining the parameters affecting the

speed of blocking-based busbar protection schemes.

CONCLUSIONS

With IEC 61850 and GOOSE cost-efcient solutions can be built,as hardwired signal paths are replaced by a LAN network.

Utilizing IEC 61850 and GOOSE boost signalling perormance andspeed which surpass those o traditional hardwired systems.Additionally, the use o IEC 61850 and GOOSE provides increased

operating reliability o the protection through continuous supervi-sion o the communication and the data integrity o the GOOSE

messages.

Furthermore, exible protection schemes can be implementedthrough sotware confgurations rather than hardwired signal

paths. This makes the system easily extendable and reconfgura-ble on demand to meet the needs o protection system changes,

as well as changes in substation confgurations and network

topologies.

Antti HAKALA-RANTAABB Oy, Distribution Automation

Olli RINTAMKIABB Oy, Distribution Automation

Janne STARCKABB Oy, Distribution Automation

For more inormation please contact:

ABB Oy, Distribution AutomationP.O. Box 699FI-65101 VAASA, FinlandPhone: +358 10 22 11Fax: +358 10 22 41094www.abb.com/substationautomation

REF615 application with GOOSE

Issues affecting the operating time of blocking-based busbar protection systems

Not affected by the applied communication technology Function gaining speed from GOOSE Significant technolgy-related delay Delay eliminated in GOOSE application

FACTORHARDWIRED

APPLICATION

IEC 61850

AND GOOSE

Safety margin allowing for a possible saturation of the

current transformers Delay originating from possible interposing relay Start delay of relay sending out blocking signal /

Overcurrent stage sending out GOOSE message Retardation time of overcurrent relay providing busbarprotection Input and blocking circuit delay / Overcurrent stage

receiving GOOSE message Circuit breaker operating time

02- utilizing possibilities of iec 61850 and goose

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